Tens of thousands of volunteers in California gather regularly at local beach and coastal cleanups in an effort to reduce trash flows that contribute to the rising amount of marine debris. These efforts make a difference and help heighten civic awareness about keeping our beaches clean and healthy. But they cannot stem the tide of plastic pollution. To do that, we need to address the problem at its source. Such action will also be a major step toward lowering the high costs to California cities and taxpayers of dealing with this waste.

A just-released analysis by the Natural Resources Defense Council of 95 California cities found that regardless of their size and distance from the ocean, these communities are spending significant sums — a total of nearly $500 million annually — cleaning up litter and preventing trash from entering waterways. The Top 10 are Los Angeles ($36.3 million), San Diego ($14 million), Long Beach ($13 million), San Jose ($8.8 million), Oakland ($8.3 million), Sacramento ($2.6 million), Hayward ($2.3 million), Merced ($2.3 million), Redondo Beach ($2.1 million) and South Gate ($1.7 million).

That's money down the drain that could otherwise be invested in other public services such as schools, firefighting, police departments or improving public parks and other open spaces.

This year, the Los Angeles City Council approved a plan to phase out single-use plastic bags, becoming the largest U.S. city to ban plastic bags at grocery stores, corner markets and big-box retailers. Los Angeles joins more than 70 communities across California as part of a growing movement to curtail the use of plastic bags, one of the most common plastic items that end up in landfills or as litter that makes its way into the ocean.

Although restricting plastic bags is an important way to tackle the increasing problem of marine plastic pollution, any beachgoer knows bags are far from the only trash you'll find at the shore. Polystyrene food packaging and containers, to-go ware, straws, bottles and bottle caps are also becoming a blight on our communities and a burden on local governments because of improper disposal. CalRecycle, the state agency that regulates disposal and recycling, estimates that Californians dump 3.8 million tons of plastic into state landfills every year — waste that could be recycled or avoided altogether.

In fact, we discard far more plastic than we recycle or reuse, much of it into rivers, lakes, beaches and, ultimately, the ocean. It kills birds, turtles, dolphins and other marine life, creates navigational hazards, imposes costs on local governments and businesses (costs we all pay), and may even threaten human health.

Plastic's durability, light weight and low cost make it a useful material for many long-term applications. But if one tallies the environmental and economic costs of using a highly persistent material for a single-use disposable item, it becomes abundantly clear that in most cases those costs outweigh the benefits.

To curtail the proliferation of plastic litter, waste management coalitions and oceans groups in California are crafting legislation that would hold producers of plastic packaging more accountable for this pollution. This proposal would address many different types of single-use plastics by creating incentives for industry to use less plastic packaging for their products, make them recyclable and ensure that recycling actually happens. It would also allocate to producers a fair share of the costs for street and beach cleanups so local governments and residents don't carry the burden alone.

Plastic producers can also play a critical role in helping curb plastic pollution by designing and promoting innovative new products. Reusable bags, cups and bottles are early examples of such innovations, but companies need to do more to reduce packaging or ensure that it is recycled. We all have a stake in keeping our communities, beaches, rivers, lakes and oceans clean so they thrive — from marine life that depends on healthy ecosystems to people who relish sunny days at the beach.

Karen Garrison is the co-director of the Natural Resources Defense Council's Ocean Program and the recipient of the 2013 "Hero of the Seas" award by the Peter Benchley Ocean Awards.

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